Bag type fluid filters are generally comprised of a fluid pervious filter bag fixed to a rigid filter collar that is disposed on an annular shoulder in a filter housing. In principle, material, such as a fluid or a fluid-solid mixture, that flows through the housing is filtered through the filter bag to remove particulate matter suspended in the fluid. Invariably, some of the fluid that flows through the filter housing is not filtered by the filter bag because the fluid flows between the filter collar and the annular shoulder thereby circumventing the filter bag. To address this problem, it has in the past been suggested to form a fluid impervious seal between the filter collar and the shoulder of the housing to prevent the flow of fluid therebetween. For example, it is known to dispose a seal or gasket between the filter collar and the annular shoulder, or to fabricate the filter collar from a material that forms a fluid impervious seal between the filter collar and the annular shoulder. These proposed methods of forming a fluid impervious seal between the filter collar and the annular shoulder generally require that an external force be applied to the rigid filter collar to form and maintain the seal. For example, the filter collar may be fastened to the annular shoulder by one or more fasteners, or the filter collar may be clamped between the annular shoulder and a housing cap. Other proposed methods of forming a seal between the filter collar and the annular shoulder include fabricating fluid impervious filter collars having a lip or flange that snap fits into an annular receiving groove proximate the annular shoulder. All of the proposed methods and apparatuses for preventing the flow of fluid between the filter collar and the shoulder of the housing have the disadvantage that they require additional structure, precise dimensions or skilled installation to ensure the formation of a seal. Furthermore, the proposed solutions are expensive and, from a practical standpoint, often do not form a satisfactory seal resulting in the passage of unfiltered material through the filter housing. There is therefore a demonstrated need for an advancement in the art of filtering a material that flows through a filter housing.
It is an object of the present invention to provide a novel method and apparatus for filtering material that flows through a filter housing.
It is a another object of the present invention to provide a novel non-sealing filter element.
It is a another object of the present invention to provide a novel non-sealing filter element that is economical to manufacture.
It is a further object of the present invention to provide a novel non-sealing filter element having a fluid pervious filter bag fixedly disposed on a non-sealing shape retaining filter collar assembly.
It is a further object of the present invention to provide a novel non-sealing filter element having a fluid pervious filter bag disposed on a non-sealing shape retaining filter collar assembly wherein the non-sealing shape retaining filter collar includes a fluid pervious annular filter element.
It is a further object of the present invention to provide a novel non-sealing filter element having a fluid pervious filter bag disposed on a non-sealing shape retaining filter collar assembly wherein the non-sealing shape retaining filter collar assembly includes a fluid pervious or impervious outturned annular flange and a fluid pervious annular filter element.
Accordingly, the present invention is directed toward a method and apparatus for filtering material that flows through a filter housing having a housing chamber, a material inlet port, a material outlet port, and an annular shoulder disposed in the housing chamber. A non-sealing filter element having a fluid pervious filter bag fixed to a shape retaining filter collar assembly including an annular sleeve, an outturned annular flange and a fluid pervious annular filter element is disposed on the annular shoulder of the housing chamber. The fluid pervious annular filter element may be a separate element interposing the outturned annular flange of the shape retaining filter collar assembly and the annular shoulder of the filter housing to filter material not filtered by the fluid pervious filter bag. Alternatively, the outturned annular flange or the annular sleeve of the non-sealing shape retaining filter collar may be comprised of a fluid pervious material to filter material not filtered by the fluid pervious filter bag.
These and other objects, features and advantages of the present invention will become apparent upon consideration of the following Detailed Description of the Invention with the accompanying drawings.